Full Surface Ion Beam Etching on 200 mm Wafers

The scia Mill 200 is designed for structuring of complex multilayers of various materials. For an exact process control different end point detection systems can be equipped. With its fully reactive gas compatibility the system enables reactive etching processes with enhanced selectivity and rate. The flexible design of the scia Mill 200 allows to adapt it as single substrate version as well as in high volume production cluster layout with up to three process chambers and two cassette load locks.

Features & Benefits

Etching angle adjustment with tiltable and rotatable substrate holder
Excellent uniformity without shaper
Enhanced selectivity and rate with reactive gases
Process control with exact SIMS based or optical end point detection
Processing of wafers with photoresist masks due to good wafer cooling
Fully automatic cassette handling in variable cluster layouts including SECS/GEM communication

Cluster layout with 3 process chambers and cassette handling

Cluster layout with 2 process chambers and cassette handling

Single chamber with single substrate load lock

Applications

Etching of a layer stack for a spintronic sensor using SIMS spectroscopy, allows to determine the layer change boundaries, thereby changing points for angle and etch stops can precisely be defined. Left: Layer stack. Right: SIMS material detection.

Structuring of magnetic memory (MRAM) and sensors (IR, GMR, TMR)
Milling of metals in MEMS production (Au, Ru, Ta, …)
Milling of multilayers from diversified metal and dielectric materials
RIBE or CAIBE of compound semiconductors (GaAs, GaN, InP, …)
Production of 3-dimensional optoelectronic microstructures
Ion beam smoothing for reduction of microroughness
Pattern transfer for optical gratings

Principle

Ion Beam Etching (IBE) / Ion Beam Milling (IBM), Reactive Ion Beam Etching (RIBE), Chemically Assisted Ion Beam Etching (CAIBE)
- Circular ion beam source etches full substrate area under a defined angle with inert or reactive gases

Technical Data

Substrate size (up to)	200 mm dia.
Substrate holder	Water cooled, helium backside cooling contact, substrate rotation 5 to 20 rpm, tiltable in-situ from 0° to 175° in 0.1° steps
Ion beam source	350 mm circular RF source (RF350-e)
Neutralizer	RF plasma bridge neutralizer (N-RF)
Typical removal rates	Cu: 44 nm/min, Pt: 35 nm/min, W:17 nm/min, SiO₂:20 nm/min
Uniformity variation	≤ 1 % (σ/mean)
Throughput	12 Wafer/h (100 nm SiO₂ on 200 mm wafer)
Base pressure	< 5 x 10^-7 mbar
System dimension (W x D x H)	3.20 m x 2.50 m x 2.50 m, for 3 chambers and cassette handling (without electrical racks and pumps)
Configurations	Single chamber, optional single substrate load lock or cassette handling, Cluster system with up to 3 process chambers and cassette handling, optional OES or SIMS based end point detection
Software interfaces	SECS II / GEM, OPC